ECG

Question 1

P wave

Answer 1

• The first event in the cardiac cycle is the depolarisation of the sino atrial node
Dp from right to left atria
Generates P wave
Reflect SA node activity

Question 2

PR Interval

Answer 2

Dp spreads thru AV node to ventricle
Conduction thru AV node is slowed to allow ventricles to be filled
Slowed conduction = PR Interval

Question 3

duration of PR Interval

Answer 3

more than 0.12 s but less than 0.2 s

>0.12. and <0.2

Question 4

QRS Complex

Answer 4

Conduction from AV node to Bundle of His through Purkinje fibres and epicardium
QRS complex does not need to have all 3 componenets

Question 5

Q wave

Answer 5

a negative wave preceding the R wave
depolarisation of ventricular septum
in I II AvL V5 V6

Question 6

R wave

Answer 6

upward deflection

Question 7

S wave

Answer 7

deflection below the isoelectric line

Question 8

T wave

Answer 8

depolarisation frome endocardium to epicardium
repolarisation in opposite direction - epicardium to endocardium
when it moves in opposite direction the T wave is in same deflection as QRS complex

Question 9

U waves

Answer 9

small deflections in same direction as T wave

Question 10

T wave does not measure depolarisation of atria but depolarisation of endocardium and epicardium why

Answer 10

ventricular repolarisation

look back at it

Question 11

limb leads

Answer 11

I, II, III

Question 12

Augmented leads

Answer 12

AvR, AvL, AvF

Question 13

limb leads and augmented leads view heart in what plane

Answer 13

vertical plane

Question 14

chest leads view the heart in what plane

Answer 14

horizontal plane

Question 15

T wave is always in the ___ direction as the QRS Complex

Answer 15

same direction

Question 16

Lead I

Answer 16

from right arm to left arm

Question 17

Lead II

Answer 17

From right arm to left leg

Question 18

Lead III

Answer 18

From left arm to left leg

Question 19

Lead AvF

Answer 19

lead I to left leg

Question 20

Lead AvL

Answer 20

lead II to left arm

Question 21

Lead AvR

Answer 21

lead III to right arm

Question 22

anterior surface seen in leads

Answer 22

V1
V2
V3
V4

Question 23

Lateral surface in seen in leads

Answer 23

I
AvL
V5
V6

Question 24

Inferior surface in seen in leads

Answer 24

II
III
AvF

Question 25

Right side of the heart seen in leads

Answer 25

AvR | V1

Question 26

chest leads

Answer 26

V1 - V6

Question 27

How is rhythm important in reporting the ECG

Answer 27

Rate should be ~60-100 bpm in the R-R Interval Regular pattern Every P wave should produce a QRS Complex

Question 28

Conduction Intervals

Answer 28

Conduction thru AV Node is slowed and produces PR interval of 0.12-0.2s Depolarisation of ventricles is rapid and spreads equally to left and right = QRS should be narrow w/ a single peak

Question 29

AvL detects nothing because...

Answer 29

perpendicular to the flow of depolarisation

Question 30

Cardiac Axis

Answer 30

cardiac axis represents the general direction of depolarisation w/ the heart starts in top right (SA node) and spreads to bottom left and apex of heart

Question 31

what does cardiac axis determine

Answer 31

determines whether a particular lead is large | or small, positive or negative.

Question 32

aVL meaning and the location of the positive electrode

Answer 32

Lead aVL Augmented Vector Left, positive electrode left shoulder.

Question 33

aVR meaning and the location of the positive electrode

Answer 33

Lead aVR Augmented Vector Right, positive electrode right shoulder.

Question 34

aVF

Answer 34

Lead aVF Augmented Vector Foot, positive electrode on Foot.

Question 35

where is V1 positioned

Answer 35

Fourth intercostals space, right sterna border

Question 36

where is V2 positioned

Answer 36

Fourth intercostals space, left sterna border

Question 37

where is V3 positioned

Answer 37

One-half way between V2 and V4 in straight line with them

Question 38

where is V4 positioned

Answer 38

Fifth intercostals space, left midclavicular line

Question 39

where is V5 positioned

Answer 39

Fifth intercostals space, left anterior auxiliary line

Question 40

where is V6 positioned

Answer 40

Fifth intercostals space, left midauxiliary line.

Question 41

what leads detects the inferior wall of the left ventricle

Answer 41

II, III aVF

Question 42

what leads detect lateral wall of the left ventricle

Answer 42

I, aVL, V5, V6

Question 43

what leads detect lateral wall of the intraventricular septum

Answer 43

V1, V2

Question 44

what leads detect anterior wall of the left ventricle

Answer 44

V3, V4

Question 45

what leads detect anterior wall of the left ventricle

Answer 45

V3R, V4R

Question 46

what leads detect posterior left ventricle

Answer 46

V7, V8, V9